[Ed. Note: The Federation of American Scientist's "Secrecy News" posted
this. For active hyper-links, go to the FAS site:
http://www.fas.org/blog/secrecy/2008/01/nsa_releases_history_of_americ.html ]
NSA Releases History of American SIGINT and the Vietnam War
During the Vietnam War, North Vietnamese intelligence units sometimes
succeeded in penetrating Allied communications systems, and they could
monitor Allied message traffic from within. But sometimes they did more
than that.
On several occasions "the communists were able, by communicating on Allied
radio nets, to call in Allied artillery or air strikes on American units."
That is just one passing observation (at p. 392) in an exhaustive history
of American signals intelligence (SIGINT) in the Vietnam War that has just
been declassified and released by the National Security Agency.
From the first intercepted cable -- a 1945 message from Ho Chi Minh to
Joseph Stalin -- to the final evacuation of SIGINT personnel from Saigon,
the 500-page NSA volume, called "Spartans in Darkness," retells the
history of the Vietnam War from the perspective of signals intelligence.
The most sensational part of the history (which was excerpted and
disclosed by the NSA two years ago) is the recounting of the 1964 Gulf of
Tonkin Incident, in which a reported North Vietnamese attack on U.S.
forces triggered a major escalation of the war. The author demonstrates
that not only is it not true, as Secretary of Defense Robert McNamara told
Congress, that the evidence of an attack was "unimpeachable," but that to
the contrary, a review of the classified signals intelligence proves that
"no attack happened that night."
Several other important Vietnam War-era episodes are elucidated by the
contribution of SIGINT, including the Tet Offensive, the attempted rescue
of U.S. prisoners of war from Son Tay prison, and more.
The author, Robert J. Hanyok, writes in a lively, occasionally florid
style that is accessible even to those who are not well-versed in the
history of SIGINT or Vietnam.
The 2002 study was released in response to a Mandatory Declassification
Review request filed by Michael Ravnitzky. About 95% of the document was
declassified. (Unfortunately, several of the pages were poorly reproduced
by NSA and are difficult to read. A cleaner, clearer copy will need to be
obtained.)
See "Spartans in Darkness: American SIGINT and the Indochina War,
1945-1975" by Robert J. Hanyok, Center for Cryptologic History, National
Security Agency, 2002.